Traditional product review systems on e-commerce websites allow users to view product reviews prior to making a purchase. Users may be able to post their own reviews and view others' reviews and ratings regarding a product of interest. Users can also search or filter through the reviews to identify a review that may be more relevant to them than others. For example, the user may filter based on demographic or geographic information. In general, the more knowledgeable a reviewer is about a product and a user, the more helpful the reviewer's review on the product is likely to be to the user.